The prior art ball-point pen can receive only one a reservoir tube and so once the ink in the reservoir tube is used up, it is necessary to replace the reservoir tube with a new one. However, the ball-point pen and the spare reservoir tubes are usually stored in different places thereby often causing the user to spend much time in finding the spare reservoir tube.
Therefore, it is an object of the present invention to provide a binder for reservoir tubes which may obviate and mitigate the above-mentioned drawbacks.